Would you rather do business with a pickled herring monger or a pickled-herring monger?

In the first example, the ‘short story writer’ is a writer who is short in stature, while the ‘short-story writer’ is some one who writes stories that are short. We don’t know how tall the second writer is, but we know his stories are short.

… The bottom line is: if you can rearrange the phrase using just the word “of,” you need to use the hyphen. If it takes any more than that for the phrase to make sense, then no hyphen.

Here’s the short rule about hyphens, straight from Strunk and White’s The Elements of Style: “When two or more words are combined to form a compound adjective, a hyphen is usually required.” Here’s the exception: Adverbs ending in -ly are never hyphenated.

Punctuation exists to make our writing clearer and to avoid confusion. Hyphens contribute to both, and they are indeed necessary in compound adjectives.

For example, if you write “a small engine mechanic,” you have just said that he’s an engine mechanic who is small (in stature). If, however, you write “a small-engine mechanic,” then you have indicated a mechanic who works on small engines. If the latter is true, then you need the hyphen. Here are other examples:

Real-time computing

Three-bedroom house

Nine-page document

Two-day vacation

Money-back guarantee

Sydney-based company

Second-rate actor

Once-in-a-lifetime experience

Back to the exception. Never use a hyphen adjoining adverbs ending in -ly to another word:

Naturally occurring event

Overly processed food

Gently ebbing waves

Richly scented perfume

Heavily weighted bookcase

Generally stated observation

It should be noted that over-hyphenating is considered as poor style as failure to hyphenate. Consider whether a hyphen is really needed when attaching prefixes to root words, such as in the following: nontraditional, overuse, pretest and unencumbered. (No hyphen is necessary in any of those words.) Furthermore, don’t hyphenate words that are actually one word; for example, online, wildlife and bellboy.

Hyphens with prefixes

When the last letter of a single-syllable prefix is a vowel and the word that follows begins with the same vowel, a hyphen is often inserted to prevent misreading.

For example:

De-emphasise not deemphasise

Re-enter not reenter

This practice is less crucial if a word is well known, or at least familiar to readers of the particular publication. Thus as both the Australian Oxford and Macquarie dictionaries confirm, cooperate, coordinateand their derivatives are no longer hyphenated.

The combination of two different vowels does not usually require a hyphen—as in prearrange, reallocate and triennial. The only exception is when a hyphen is used to separate the prefix from a single-syllable word beginning with a vowel, to prevent the two parts from being read together as one syllable: de-ice not deice.

Hyphens are used with co- (‘joint’) and ex- (‘former’) in recent formation, whether or not the word attached begins with a vowel:

Co-author, co-worker, ex-alderman, ex-president

For a growing set of words prefixed with e (for electronic), hyphenation is recommended:

e-book, e-business, e-commerce, e-shares, e-shopping, e-zine

The e prefix is so small that such words would be in danger of being misread unless the hyphen is there.

email no longer takes a hyphen

Hyphens are needed if a prefix isfollowed by capital letter, a number, or an expression that is in italics or quotation marks. For example:

Hyphen and em rule/dash: not to be confused

The Em Rule (Dash): Long and Lean

Use an em rule/dash to show a sudden change of thought. Example: An archaeologist—of course I don’t mean you—is a person whose career lies in ruins.

Use an em rule/dash before a summary of what is stated in the sentence. Example: Avoiding work, getting liposuction, becoming a finalist in the George Hamilton Cocoa Butter Open—everything depends on that trust fund.

The Hyphen: Short and Sweet

The hyphen, in contrast, is used to show a break in words.

You could make it through life fine and dandy without a dash, but you’d be the poorer for it. Like argyle socks, the dash shows flair and style. It creates rhythm and emphasis in your writing.

The Ellipsis: Dot, Dot, Dot

The ellipsis, in contrast, indicates a break in continuity. Example: Abraham Lincoln said: “Four score and seven years ago our fathers brought forth … a new nation, conceived in liberty and dedicated to the proposition that all men are created equal.”

Use an ellipsis to show a pause or interruption. Example: “No,” I said. “I … I need my space.”

Regarding using hyphens at the end of a line of text: The dreaded but often hilarious hyp-hen has died. With improved technology, today’s newspapers and magazines rarely break words that used to over-run column width with wrongly-placed hyphens in a way that led to mans-laughter and other typographical leg-ends. (from fun-with-words)